Sub placement question

[clpetersen]

Originally Posted by littlegiant

Also, l'm new to subwoofers. After reading some forums there appears to be a couple of basic low cost items I should purchase. First is some sort of CD with low pitched tones to help me get the subwoofer phase matched to the mains. And second is a meter to measure the volume of the sub as I place it in different positions. Specifically what are these items and where can I purchase them?

Thank you.

A good test CD not much money (about $20) is the Sound Doctor Test CD. Along with the CD, download the white paper form the Sound Doctor (free). Read the paper first, maybe twice.

I did this as well as borrow a meter from the dealer and set-up REW software. I am reasonably conversant in digital signal processing, and my conclusion with the meter and waterfall diagrams etc., was:
1) it varies a lot from position to position; probably indicative that room acoustic treatments would be the first order of business for our space.
2) it is a powerful tool. In the hands of novices it could cause more harm than good and turn into a major rabbit hole. I did not use it but relied on my perceptions, the white paper, and the infamous 'sub-crawl'.

In the end, and somewhat surprising (to me at least), the subs (left/right pair) ended up much closer to the listening spot than the mains are. Works great in our space.

Have fun!

A good music test CD, lent to me by the Boston area dealer: Boz Scaggs 'Dig'.

[crwilli]

Originally Posted by clpetersen

A good test CD not much money (about $20) is the Sound Doctor Test CD. Along with the CD, download the white paper form the Sound Doctor (free). Read the paper first, maybe twice. I did this as well as borrow a meter from the dealer and set-up REW software. I am reasonably conversant in digital signal processing, and my conclusion with the meter and waterfall diagrams etc., was: 1) it varies a lot from position to position; probably indicative that room acoustic treatments would be the first order of business for our space. 2) it is a powerful tool. In the hands of novices it could cause more harm than good and turn into a major rabbit hole. I did not use it but relied on my perceptions, the white paper, and the infamous 'sub-crawl'. In the end, and somewhat surprising (to me at least), the subs (left/right pair) ended up much closer to the listening spot than the mains are. Works great in our space. Have fun! A good music test CD, lent to me by the Boston area dealer: Boz Scaggs 'Dig'.

One feature of REW I found helpful was the modeling function. If your room is fairly rectangular, as mine is, you can enter its dimensions, your speaker, sub and listening position and then see what happens to the low end as you try efferent locations for them in your modeled room. It was not the end all but did allow me to see where suck outs at my listening position were minimized and was either a few niches f where my sub ended up. Of course, change one thing at a time! E.g fix your listening position and the position of your mains and just move the sub around in the model.

The model did correlate quite well for my actual measurements - from 300Hz down because my room is fairly symmetrical.

[clpetersen]

Good point (room modeling).
I did not explore this feature, went straight to measurements.

Might look at this further.

[crwilli]

Originally Posted by clpetersen

Good point (room modeling). I did not explore this feature, went straight to measurements. Might look at this further.

Heck of a lot easier than crawling around or moving a 150+ lb. sub and stand around a room.

[littlegiant]

Thanks a lot.

Do you have any recommendations for an affordable meter to measure speaker volumes to help match subwoofer phasing?

[crwilli]

Originally Posted by littlegiant

Thanks a lot. Do you have any recommendations for an affordable meter to measure speaker volumes to help match subwoofer phasing?

Radio Shack 33-2055

[clpetersen]

Originally Posted by littlegiant

Thanks a lot.

Do you have any recommendations for an affordable meter to measure speaker volumes to help match subwoofer phasing?

You may also want to read up on REW software as well:

https://dl.dropboxusercontent.com/u/...%20Version.pdf

This is a nice guide, updated frequently (last update August 2016).